International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 06 Issue: 04 | Apr 2019
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Design of Steering & Braking System for Self Propelled Onion
Harvester
Prof. V.I. Pasare1, Satyam N. Gadekar2, Pratik B. Kanase3, Rajesh R. Kadam4,
Ranjeetsinh R, Jadhav5, Vishvajeet R. Wadkar6
Dept. of Mechanical Engineering, DYPCET, Kolhapur, Maharashtra, India
Dept. of Mechanical Engineering, D.Y.Patil College of Engineering & Technology, Maharashtra, India
---------------------------------------------------------------------***---------------------------------------------------------------------
2,3,4,5,6Student,
1Professor,
Abstract – The basic idea is to provide a easy maneuverability
with effective control. The provision of camber and caster
should be provided according to the actual field condition such
that there should be straight ahead movement with minimum
turning effort. The machine should be compact so that frame
design based on steering parameters so we decided the
compact condition with minimum turning radius. The machine
is going to be operated in the field so that maximum speed will
in the range of 14 to 15 km/hr. According to that braking time
and stopping distance is being calculated for effective braking.
)
only leads to stopping in shorter time, may also cause injury
to the driver due to high decelerating forces. It also causes
rapid wear brakes & more risk of losing control of vehicle.
Braking efficiency of the order 50-80 enable to stop within
reasonable distance. However stopping distance varies with
road condition and condition of tires. We have selected the
wheels size according to design requirements. For better
traction & more grip on uneven agricultural field, the thread
pattern are more suitable. Both the front & rear wheels are
thread pattern type. Their biggest advantage is that they do
not slip on sharp turns this feature make it suitable for
agriculture application. It carries load of machineries these
thread keep it inside the rim also. The ply rating also paly
important role, more ply indicate more load carrying
capacity. We have selected the wheels which has more ply
rating.
Key Words: Productivity, Steering Mechanism, Turning
Radius, Braking Distance
1. INTRODUCTION
Our challenge is to design the steering mechanism for the
agricultural machine. As agricultural machine have high
strength and robust, reliable, optimum and efficient. When
the machine is on actual field better turning effect with easy
manoeuvrability. For this we have applied Ackerman
steering principle and rack and pinion mechanism. Rack and
pinion mechanism has fewer rotary parts and simple in
construction. Braking mechanism is basically to stop the
machine with minimum time and minimum stoppage
distance. For that effective utilization of resources with
conditioning is being applied,
1.2 Objectives for Self Propelled Onion Harvester
According to customer voice and product demand we set our
goals and objectives which contains design and fabrication of
self-propelled onion harvester with
 Best machine field efficiency
 With best crop (Onion) digging ability
 Minimum consumption of fuel during the field
operation
 With maximum machine field efficiency.
 Best machine farm efficiency.
 Good material handling and operator field
comfort
 Minimum damage to crop (Onion)
1.1 Problem Statement
In market survey for this onion harvester we come to know
that customers were emphasized on the minimum turning
radius. Any agriculture machine should move with minimum
turning radius. By considering the bed size in the actual
onion field, the beds are apart from its immediate at 450 mm
.So our challenge was to design a steering system which
gives minimum turning radius. So that the machine should
take a immediate bed after harvesting the first bed.
2. Methodology
By understanding the customer voices and product demand
related with the onion harvesting machine, we established
some factors which can make the machine more optimum,
reliable, efficient and cost associative. These factors can be
stated as, the machine should have easily serviceable parts in
case of breakdown. It should have the best payback period, It
should be suitable for different soil conditions,
Braking system is an important system for tractors used to
slow down the motion or stop the tractor motion after
applying the brakes a machine should stop at minimum
distance.
Our challenge was to design a braking system gives a good
braking efficiency. However higher braking efficiency not
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Volume: 06 Issue: 04 | Apr 2019
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Sr. No
Parameter
Specification
1
Machine Type
4 Wheel
2
Overall dimensions (L x B x
H)
2550 x 1600 x
1776 mm
3
Static Ground Clearance
300 mm
4
Machine weight
570 kg
5
Wheel Base
1550 mm
6
Wheel track width
1450 mm
7
CG location from machine
mid plane & wheel Centre
367mm
8
Max. Speed
15 km/hr
9
Working Width
900 mm
10
Working Depth
100 mm
11
Volume of Material Handled
0.045 m³/sec

3. OVERALL TECHNICAL SPECIFICATIONS OF MACHINE
3.1 Design of Steering System
Requirements of Steering System
Table -1: Overall Machine Specifications
Digging and Conveyor System
Replaceable Blades
Adjustable Cutting Depth with Hydraulic Jack
Mechanism
Effective Blade Geometry
Better Separating Index
Engage and Disengage Mechanism for Conveyor
Drive




Steering System
Adjustable Camber
Effective turning radius
Provides better control on uneven agriculture field


Power Transmission System
Provide best performance on field by providing
effective torque at wheel and best tractive effort.


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Impact Factor value: 7.211

The effort required to steer should be minimum.

The steering mechanism should also provide the
directional stability. This implies that the machine
should return to its original position quickly after
removing hand from wheel.

It should provide easy maneuverability.

The design should be such that it should transfer
less shocks to driving wheel.
Table -2: Steering System Specifications
Steering System Specifications
Machine Frame
Provide structural support to the machine
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The steering mechanism should be effective and
easy to operate.
The intention of Ackermann geometry is to avoid the need
for tires to slip sideways when following the path around a
curve. The geometrical solution to this is for all wheels to
have their axles arranged as radii of circles with a common
center point. A linkage between these hubs pivots the two
wheels together, and by careful arrangement of the linkage
dimensions the Ackermann geometry could be
approximated. This was achieved by making the linkage not
a simple parallelogram, but by making the length of the track
rod (the moving link between the hubs) shorter than that of
the axle, so that the steering arms of the hubs appeared to
"toe out".
According to that we divided the machine into different
subsystems according to its working principle and
mechanism. Following figure gives brief introduction about
each system and its features.




3.2 Selected Mechanism: Ackerman Geometry
To work on the above factors we decided the strategy to
design and fabricate the onion harvester which can perform
effectively with most innovative and optimum features.



Provides better ergonomic considerations by
providing good visibility assistance, accessibility of
controls and safety.
|
Type of Steering System
Rack & Pinion
type
Inner Wheel Angle (Θ)
42°
Outer Wheel Angle (Φ)
27.1 °
Ackerman %
70%
Turning Radius (R)
2.859 m
King Pin Inclination (KPI)
+ 80
Camber
+2°
Caster
+6°
Scrub Radius
0.11 m
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Furthermore, the availability of this steering box is high in
the market and spare parts are easily available. Hence
Maruti 800 was the best possible option.
Other Parameters
Track Width
1450 mm
Wheel Base
1550 mm
Steering Gear Box Ratio
18:1
Steering Arm
125 mm
Steering Gear Box Ratio / Steering Ratio: 18:1
The requirement of the steering gear box for this particular
vehicle was in the range of 10:1 to 20:1. The steering gear
box of Maruti 800 was a perfect selection for it. It has a
steering ratio of 18:1.
3.5 Inner Wheel Angle: 42o
The inner angle is the angle of the inner wheel taking a right
or a left turn by locking the steering wheel to the extreme
position. The turning radius to be met was below 3.5m.
Hence after permutation and combination of all the factors,
we selected 40o which was sufficient in all terms.
3.6 Outer Wheel Angle: 27.1o
The outer angle according to assuming the inner angle to be
40 degree is calculated by the following formula as follows,
420
1450
𝑐
27.10
𝑐𝑜𝑡∅ − 𝑐𝑜𝑡𝜃 =
𝑏
𝑐
𝑐𝑜𝑡∅ =
Fig -1: Ackerman Steering Geometry
+ 𝑐𝑜𝑡𝜃
𝑏
3.3 Selected Gear Box Type: Rack And Pinion
The rack carries the full load of the actuator directly and so
the driving pinion is usually small, so that the gear ratio
reduces the torque required. This force, thus torque, may
still be substantial and so it is common for there to be a
reduction gear immediately before this by either a gear or
worm gear reduction.
3.4 Selected Steering Ratio and Steering Gear Box:
Ф= 27.1°
Steering Ratio
3.7 Turning Radius: 2.859m
Considering the vehicle to be partially a prototype of tractor
and partially an ATV, the steering ratio had to be in between
the 10:1 to 20:1. The steering effort had to be less, looking at
the different operation a driver has to do while driving the
vehicle and also while harvesting the onions. Various gear
box of tractors as well as cars were studied. The most suited
to ratio is between 15:1-20:1 for this vehicle.
The diameter of the smallest circle which the outer front
wheel of the car can traverse and obtain when the wheels
are at the extreme position is known as turning radius.
Requirement: The turning radius for this onion harvester
was to be kept below 3.5 m. This was for easy
maneuverability of the vehicle from onion bed to bed.
Steering Gear Box
Now Why MARUTI 800? The reason for fixing this particular
gear box it that, it is a proven gear box for almost all the
ATV’s. The structure of its entire steering system is rugged
and has strength to handle weight of about 1 tonne.
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Actual turning radius of the vehicle is an average of RIF and
ROF.
3.8 Calculations
R =
(RIF+ROF)/2
R= 2.859 m
CASTOR: +6°
The caster angle or castor angle is the angular displacement
of the steering axis from the vertical axis of a steered wheel
in a car, motorcycle, bicycle or other vehicle, measured in the
longitudinal direction. It is the angle between the pivot line
(in a car an imaginary line that runs through the center of
the upper ball joint to the center of the lower ball joint) and
vertical. For agricultural vehicles there is no castor
implemented. But considering the ATV condition and
requirement of the vehicle for running it in the onion field
castor of 30 was decided to be implemented to attain the
straight motion of the vehicle while plucking the onions. The
recommended range is between 3-6 0
Fig -2: Steering Geometry
CAMBER: +2°
Camber angle is the angle made by the wheels of a vehicle;
specifically, it is the angle between the vertical axis of the
wheels used for steering and the vertical axis of the vehicle
when viewed from the front or rear. The positive camber
angle gives greater stability on uneven surfaces. Tractors
ordinarily designed with considerable amount of camber as
they frequently required to operate on uneven surface
largely counteracts the tendency of cambered wheels to turn
outwards though they were large cones turning around
there apexes . The correct camber for this vehicle was in
between the range of 1.570..
Turning radius for inner front wheel,
RIF
Turning radius for outer front wheel,
ROF
Parameters taken from the actual prototype,
King Pin Inclination: +80
b= 1550 mm
c= 1200 mm
a= 1450mm
𝜃 = 420
On most modern designs, the kingpin angle is set relative to
the true vertical line, as viewed from the front or back of the
vehicle. It helps to reduce road shocks such as those caused
by holes, stones & high spots. A king pin inclination tends to
reduce.
∅ = 27.1
Turning radius for inner front wheel,
SCRUB RADIUS: 0.11m
RIF =
The scrub radius of your car can be altered with different
wheel offset and suspension design. A positive scrub radius
tends to be beneficial while braking into a turn. A negative
scrub radius tends to better for braking stability in the event
of brake failure or split-mu braking. Typically, the scrub
radius is configured to be as small as possible to minimize
the effects under braking, but squirm (from zero scrub
radiuses) is also undesirable. The Scrub radius is calculated
by graphical method as follows,
RIF=2.191m
Turning radius for outer front wheel,
ROF =
Steering Arm Angle / Ackerman Angle: 30.220
ROF=3.527
sin (∝ +𝜃) + sin(𝛼 − ∅) = 2 sin 𝛼
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sin (∝ +42) + sin(𝛼 – 27.1)
direction stability & to get more grip on uneven agriculture
field. From we selected the front tires of 12”.The Dimensions
of the FRONT TIRES is as follows:
(sin ∝× cos 42+ cos ∝× sin 42) + (sin ∝ × cos 27.1 − cos ∝×
sin 27.1) = 2 sin ∝
Tire type =TT
0.2136cos ∝=0.3667 sin ∝
Outer Diameter = 588 mm
∝= 30.22°
Tire Size = 6”- 12”
Ackerman Percentage: 70% Understeer
PLY Rating = 4 Ply
Ackerman percentage decides how much your inner tire
turns compared to outer tire. 100 % Ackerman condition is
when the turning circles of both inner and outer tire are
concentric while 0 % means both circles are the same i.e.
inner tire turns the same angle that of outer tyre. In 100 %
Ackerman condition the steering arms meet at the center of
rear axle. When the Ackerman % is below 100%, the
condition is under steer and when the Ackerman percentage
is above 100% the condition is over steer.
Rim Size = 12”
Pattern =AS504
Tire pressure = 55 psi
4. Design of Braking System
Ackerman Percentage = current distance / distance for
100 % × 100 %
We have used the disc brakes on the front wheel which
provides easy breaking with minimum stoppage distance.
4.1 Objectives for Braking System
= 1085/1550 × 100 %

= 70% UNDERSTEER
To obtain high operational speed during rapid
braking and compatibility of tractor.
Taking into account traffic safety and maintenance.
To achieve minimum braking distance.
The weight distribution and large rear tires of the
machine have enable to generate sufficient braking
effort from the rear wheels alone.



3.9 Wheels and Tires
Rear Tire Selection:Selection of rear wheels were according to specification
given in the rule book , provided by SAE-TIFAN . these
wheels are used where drive is given , here are the
specification
4.2 Calculations
Dynamic axle load-
Tire Type = TT
Fzf = (1-ψ+x*a) W ………….front axle rear force
Outer Diameter = 818mm
Ψ=
Tire size = 7.5”- 16”
Where,
=
= 0.3 …………….static axle load distribution
Mf = static front axle load in kg
Pattern =AS504
M = total vehicle mass in kg
Pressure = 65 psi
x=
=
= 0.228 …………..relative C.G.
Ply rating = 8 ply
Where,
Rim size = 16”
h= height of C.G.
Front Tire Selection:-
Wb = wheel base
By considering the ground clearance which was to be
maintained 300mm above the ground, according to the
requirements on agriculture field, for better traction,
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Fzf = (1-0.3+0.228*0.25)*460
= 348.22 kg
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Front axle braking force –
= 2390.028 * 0.11
Fxf = uf * Fzf * g
= 262.903 Nm
= 0.4 * 348.22 * 9.81
Validation of satisfaction of braking torque
= 1366.42 N
Table -4: Validation of Braking Torque
Braking torque –
Txf = Fxf * Rr
= 150.306 Nm
Requirement
Generated
150.306
262.903
Where,
Stopping time – (T)
Rr = radius of disc of rotor
Txf = 1366.42 * 0.11
T=
= 150.306 Nm
=
= 2.12 sec
Validation of brake torque requirements –
Stopping distance = (S)
Master cylinder bore = 19.05 mm
Area of master cylinder = * (19.05)2 = 285.023 mm2
S=
=
= 2.17 m
Pedal force = 350 N = Fp
Pedal ratio = 5:1 = m
5. CONCLUSIONS:
Leverage efficiency = 0.8 = η
The main objective was to make simple, compact, efficient
and low cost small scale harvester for small land holders.
This machine fulfilled all objective and following conclusion
were drawn on based of work.
Force acting on master cylinder = Fmc = m * Fp* η
= 5 * 350 * 0.8
= 1400 N
With this design we can easily achieve the objectives which
have set. By this steering is effective and easy to operate. The
effort required for steering is less and provide directional
stability. It will provide easy maneuverability and less
transfer of shocks to the driver.
Pressure acted in master cylinder = (Pmc)
Pmc =
=
= 4.912 * 106
Acp = *(bcp)2 = * 442 = 1520.53 mm2
By efficient braking we have obtained high operational speed
during rapid braking. We also have taken into account traffic
and safety rules. The overall objective of machine was
fulfilled by our design. Which can help to fabricate simple,
compact, efficient and low cost harvester.
Force applied by caliper:
REFERENCES
Pmc = 4.912 bar
Area of caliper piston = (Acp)
Fp = Pmc * Acp * η
= 4.912 * 106 * 1520.53 * 0.8
[1]
Thomas D. Gillespie, Fundamentals of vehicle
dynamics, Society of Automotive Engineers, Inc. 400
commonwealth drive, Warrandale, PA 15096- 0001
[2]
Joseph Heitner, Elements of Automotive Mechanics
(2nd Edition).
[3]
R. S. Khurmi & J. K. Gupta - Machine Design- Eurasia
publishing house New Delhi,14th Edition, 2008
[4]
Theory of Machine –Rattan S.S Tata - McGraw Hill
Publishing Company New Delhi,2nd Edition,2006
= 5975.07 N
Total force applied –
FPT = fp* u
= 5975.07 * 0.4
= 2390.028 N
Torque generated Tf = FPT * R
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[5]
http://www.economicsdiscussion.net/agriculture/
problems-agriculture/indian-agriculture-problems7-major-problems-of-indian-agriculture/12859.
[6]
V.B. Bhandari “DESIGN OF MACHINE ELEMENTS”
3rd edition
[7]
Dr. Kirpal Singh, “AUTOMOBILE ENGINEERING”
VOL. 1 by 13th edition 2012, Standard publication,
Delhi 13th edition 2013.
[8]
Strength of Machine Element, Prof.R.K.Rajput
S.Chand Publication edition 2008.
[9]
Laukik P. Raut, Vishal Dhandare, Pratik Jain, Vinit
Ghike, Vineet Mishra, “Design, Development and
Fabrication of a Compact Harvester”, International
Journal for Scientific Research & Development| Vol.
2, Issue 10, 2014 | ISSN (online): 2321-0613
[10]
Government of India, “Indian agricultural statistics
2015-16”, Ministry of Agriculture & Farmers
Welfare, Department of Agriculture, Cooperation &
Farmers Welfare, Directorate of Economics &
Statistics, New Delhi
Mr. Rajesh R. Kadam
Student, Dept. of Mechanical
Engineering, D.Y.Patil College of
Engineering
&
Technology,
Maharashtra, India
Mr. Vishvajeet R. Wadkar
Student, Dept. of Mechanical
Engineering, D.Y.Patil College of
Engineering
&
Technology,
Maharashtra, India
BIOGRAPHIES
Prof. V.I.Pasare
Professor, Dept. of Mechanical
Engineering, DYPCET,Kolhapur,
Maharashtra, India
Mr. Satyam N. Gadekar
Student, Dept. of Mechanical
Engineering, D.Y.Patil College of
Engineering
&
Technology,
Maharashtra, India
Mr. Pratik B. Kanase
Student, Dept. of Mechanical
Engineering, D.Y.Patil College of
Engineering
&
Technology,
Maharashtra, India
Mr. Ranjeetsinh R. Jadhav
Student, Dept. of Mechanical
Engineering, D.Y.Patil College of
Engineering
&
Technology,
Maharashtra, India
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